Top economist says two contenders to replace Fed Chair Powell stand out
1. El-Erian favors Rieder and Warsh as top Fed chair candidates. 2. Both candidates have strong market understanding and communication skills. 3. Rieder suggests the next Fed chair must lower interest rates next year. 4. Fed leadership change may stabilize market uncertainty post-Powell. 5. A strong Fed chair could influence S&P 500 volatility.